Spatiotemporal patterns and potential sources of polychlorinated biphenyl (PCB) contamination in Scots pine (Pinus sylvestris) needles from Europe

Abstract

Using pine needles as a bio-sampler of atmospheric contamination is a relatively cheap and easy method, particularly for remote sites. Therefore, pine needles have been used to monitor a range of semi-volatile contaminants in the air. In the present study, pine needles were used to monitor polychlorinated biphenyls (PCBs) in the air at sites with different land use types in Sweden (SW), Czech Republic (CZ), and Slovakia (SK). Spatiotemporal patterns in levels and congener profiles were investigated. Multivariate analysis was used to aid source identification. A comparison was also made between the profile of indicator PCBs (ind-PCBs-PCBs 28, 52, 101, 138, 153, and 180) in pine needles and those in active and passive air samplers. Concentrations in pine needles were 220-5100 ng kg(-1) (∑18PCBs - ind-PCBs and dioxin-like PCBs (dl-PCBs)) and 0.045-1.7 ng toxic equivalent (TEQ) kg(-1) (dry weight (dw)). Thermal sources (e.g., waste incineration) were identified as important sources of PCBs in pine needles. Comparison of profiles in pine needles to active and passive air samplers showed a lesser contribution of lower molecular weight PCBs 28 and 52, as well as a greater contribution of higher molecular weight PCBs (e.g., 180) in pine needles. The dissimilarities in congener profiles were attributed to faster degradation of lower chlorinated congeners from the leaf surface or metabolism by the plant.

Passive Air Samplers As a Tool for Assessing Long-Term Trends in Atmospheric Concentrations of Semivolatile Organic Compounds

“…The underlying differential equation describing the concentration–time trend is where c denotes the concentration, t time, and k a rate constant, indicating a fraction of pollutant loss per unit of time. This corresponds to a situation of negligible emissions together with ongoing loss processes of the pollutants such as degradation, deposition, and transport. ,− …”

Comparability of long-term temporal trends of POPs from co-located active and passive air monitoring networks in Europe

“…Although PCBs are still in limited use, their atmospheric levels have decreased over the globe. 7,[33][34][35][36][44][45][46][47] Active EMEP temporal trends for all six indicator PCBs show statistically signicant (p < 0.05) decreases at Birkenes, Košetice, Pallas, Råö and Zeppelin ranging from 2-20% per year. This is supported by similar and consistent decreases in the passive MONET trends for all PCBs and all sites ranging from 1-30% per year.…”